GTT Single-phase solid state relay, up to 120A



  • The GTT family of solid-state relays has been designed with the aim of providing very accurate control of the load from an analog input signal (0-10V or 0-20/4-20mA) or a potentiometer (from 1kOhm to 10kOhm ).
  • The electronic design ensures that the cycle time for proportioning the power is automatically optimized.
  • The number of cycles that the GTT supplies to the load (fast cycling) for a given input signal is calculated to be the minimum possible to maintain the necessary accuracy.
  • This guarantees a very fast and accurate control loop that enables the GTT, driven by a controller or a PLC with analog output, to obtain very precise control.
  • The GTT can be used in three-phase systems, using master-slave control architecture in which the control signal drives only one GTT (master) and this unit supplies the synchronized signals to the other units (slaves).
  • Optional monitoring for an interrupted load can be provided (HB).
  • This accepts a 500mAac input from a current transformer.
  • The trip point is adjustable with trimpots and there is an LED indication and a normally open voltage free relay contact output.
  • The GTT solid-state relay has a green LED to indicate the presence of the 24Vac power supply and a red LED to indicate the switching state as a function of the input signal.
  • This LED will be continuously off for zero power and fully on at maximum and will flash at all intermediate values.
  • The units offer optional accessories for panel mounting, fuses and fuse holders, current transformer, and voltage transformer


Zero-voltage switching, optimised fast cycle time. Current range: 25A to 120A, diagnostics and load interrupt alarm

  • Command input from analogue voltage or current signal or potentiometer
  • Switching at voltage zero crossing
  • Partialization of wave train power with dynamically optimized time cycle
  • Antiparallel double SCR
  • 2 led for supply indication, "ON" state, 1 optional LED for load interrupt alarm
  • 4000V isolation between input circuit and power output
  • MOV (varistor)
  • Optional monitoring of interrupted load
  • DIN rail mounting (standard); Panel mounting (optional)